Here's (some of) your problems with attempting to sue the valuer:
- A valuation is ultimately an expression of opinion, even where supporting by data. You'd need to prove that the value given is sufficiently outside a reasonable range. The valuation is less than 10% different to your sale price, and 10% different to your market price - which puts it well and truly within the ballpark of a reasonable range in my thinking.
- You'd need to prove that he failed to follow some prescribed method in making the valuation. Good luck getting that together.
-There are different 'types' of valuations. As mentioned above, bank valuations tend to be very reserved.
- It's not your valuer. It's the buyer's bank's valuer. You don't have a contractual relationship with them, and they don't owe you a duty of care. Without either of those, I don't think you've even got a sufficient cause of action to start a proceeding. You could possibly get a statement of claim past a Registrar, but you'd be up against a striking out/summary judgment application faster than the ink on the Registry's seal can dry.
- You don't actually have any damages that I can see. The loss of the contract (if it does happen) may be too remote. And, it's not clear that you've lost it anyway. If the sale manages to go through then you haven't lost anything at all.
